Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add iliaal/whetstone --skill ia-react-frontendgit clone --depth 1 https://github.com/iliaal/whetstoneWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/iliaal/whetstone/ia-react-frontend)<a href="https://agentmods.dev/skills/iliaal/whetstone/ia-react-frontend"><img src="https://agentmods.dev/badge/skills/iliaal/whetstone/ia-react-frontend/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/iliaal/whetstone/ia-react-frontend"><img src="https://agentmods.dev/badge/skills/iliaal/whetstone/ia-react-frontend.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00059 | $0.00763 |
| Opus 5 | $0.00030 | $0.00381 |
| Sonnet 5 | $0.00012 | $0.00153 |
| Haiku 4.5 | $0.00006 | $0.00076 |
Grade A, and why
ia-react-frontend scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured today.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
This is a copy
89% identical to react-frontend — 8 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 76 lines — stays where its author put it; the contents beside it link to each section on GitHub.
React Frontend
Verify before implementing: For App Router patterns, React 19 APIs, or version-specific behavior, look up current docs (Context7 query-docs if available, else the framework's official docs via web search) before writing code. Training data may lag current releases.
Working rules
- Keep derived state in render and user actions in event handlers; use effects for external synchronization.
- Give async work a lifecycle and cancellation policy; represent failure separately from pending and empty data.
- Preserve focus when hiding interactive regions and exercise keyboard navigation in a real browser.
- Validate and authorize every public server action; send only needed fields across server/client boundaries.
- Measure performance changes and test user-visible behavior, not type-checking alone.
Effects Decision Tree
Effects are escape hatches -- most logic should NOT use effects.
| Need | Solution |
|---|---|
| Derived value from props/state | Calculate during render (useMemo if expensive) |
| Reset state on prop change | key prop on component |
| Respond to user event | Event handler |
| Notify parent of state change | Call onChange in event handler, or fully controlled component |
| Chain of state updates | Calculate all next state in one event handler |
| Sync with external system | Effect with cleanup |
Effect rules:
- Never suppress the linter -- fix the code instead
- Use updater functions (
setItems(prev => [...prev, item])) to remove state dependencies - Move objects/functions inside effects to stabilize dependencies
useEffectEventfor non-reactive values (e.g., theme in a connection effect)- Always return cleanup for subscriptions, connections, listeners
- Data fetching cancellation (pick by situation):
AbortControllerfor fetch;ignoreflag for non-cancellable promises; React Query handles both automatically
Discipline
- Simplicity first -- every change as simple as possible, impact minimal code
- Only touch what's necessary -- avoid introducing unrelated changes
- No hacky workarounds -- if a fix feels wrong, step back and implement the clean solution
- Before adding a new abstraction, verify it appears in 3+ places
What ships with it
6 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- today Changed · -128 lines 6655c964eb18
- yesterday First seen · 204 lines · 59 tokens per session scan A d1f46715a0c4
ia-react-frontend is a skill published in the GitHub repository iliaal/whetstone (33 stars, last pushed yesterday), licensed MIT. It adds 59 tokens to every session and 763 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 89% identical to react-frontend, differing in 8 lines, and is treated as a copy.
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